The next time I find myself in a US airport, with a typical spare three hours before my flight, I’m going to make a beeline to the nearest Butter London boutique. This nail company has rolled out a series of nail salons in Seattle and Sacramento airports, and will soon have another location in Dulles.  The company specialises in rapid but luxurious treatments in a funky setting, but even better, the nail polishes don’t have the nasty chemicals found in most brands. A manicure is just $20 while a pedicure is $40. And if you can’t make it to one of those airports, customers in the US, UK and Canada can buy the non-toxic polishes on line.